\chapter{Research Question}

The first question to ask is what is reliability is. A system is reliable if it does what you expects it to do. So if you present your users with the reality of the situation they will be satisfied if the system behaves as expected. Reliability comes down to predictable performance which is as good as possible.

We would like to see if this concept carries over to voice across MANets. We have to be realistic in that their networks are highly turbulent and that transmission of massive streams in real-time across vast expanses are unlikely realised with today's technology. By using a network aware PTT system, we want to see what the perceptions of the users are as the system moves them between synchronous and asynchronous as network conditions change.